**Core Concept**
Stem cells play a crucial role in tissue regeneration and repair by maintaining the homeostasis of various tissues, including the cornea. The cornea, being a transparent and avascular tissue, relies on a population of stem cells to maintain its clarity and function.

**Why the Correct Answer is Right**
The correct answer is related to the location of limbal stem cells in the cornea. Limbal stem cells are responsible for the renewal of corneal epithelial cells, which is essential for maintaining the integrity and transparency of the cornea. These stem cells are found in the limbal region, which is the area between the cornea and the sclera. The limbal stem cells are located in the basal layer of the limbal epithelium and are in close proximity to the corneal epithelium.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a location within the cornea where stem cells are present.
* **Option B:** This option is incorrect because it refers to the corneal endothelium, which is a layer of cells that lines the posterior surface of the cornea, but it is not the primary location of stem cells.
* **Option C:** This option is incorrect because it refers to the corneal stroma, which is the middle layer of the cornea composed of collagen and keratocytes, but it is not the primary location of stem cells.

**Clinical Pearl / High-Yield Fact**
The limbal stem cells are responsible for maintaining the corneal epithelium, and any damage to this area can lead to corneal ulcers and vision loss. This highlights the importance of preserving the limbal stem cells during surgical procedures involving the cornea.

**Correct Answer: C. Sclero-corneal junction.**